Source

Key Direction Project of Knowledge Innovation Program, Chinese Academy of Sciences

Introduction

This project preliminarily established water balance model of wetland system, revealed the spatiotemporal variations of C, N, P in main rivers and their influencing factors through the study on the matter circulation processes in wetland ecosystem of Sanjiang Plain.

Main Conclusions

I. The significant effect of hydrological regime on species density and diversity index was illuminated. The relationship between exogenous input N, P and species richness were revealed, as well as the succession drove by exogenous nutrients input and their accumulation.

II. The key roles of C/N, C/S and C/P in the elements returning were elucidated. The thresholds of C, N, and S released from mire wetland litters and their coupled relation were first defined.

III. The emission trends of greenhouse gases, H₂S and COS were revealed.

IV. The transportation processes and circulation models of C, N, S, and P were quantitatively established in wetland system. The pools of C, N, S, and P were calculated. The viewpoint that C, P, and S were in net accumulation status while N was in loss status provided theoretical basis for the management of deplaced mire wetland and insight of ecosystem functions.

V. The soil nutrients decrease and the transformation process of wetland from the C sink to C source when wetland reclaimed were illuminated. The management strategies (e.g. increasing water-collecting amount, expanding wetland buffer, regulating the C/N and C/P) of wetland protection and restoration were proposed.